Carburetor



F. A. KOMMER Get. 19, 1937.

CARBURETOR Filed May 4, 1935 INVENTOR.

BY M a FIGS .1 TTORNEY.

Patented Oct. 19, 1937.

PATENT OFFICE CABBURETOR Fred A. Kommer, St.

Louis, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application May 4, 1935, Serial No. 19,839

12 Claims.

This invention relates-to carburetors for in-' temal combustion engines, and more particularly to a new and improved pivot mounting for the float which controls the fuel intake valve for the constant level chamber. 0

In previous carburetor constructions the float has been mounted on a horizontal pin supported in the walls of the float chamber. This pin had to pass thru at least one wall in assembly and required a closure and, besides being comparatively expensive, permitted a possible fuel leakage, particularly after frequent removals and insertions of the pivot pin for the purpose of adjustmentor replacement of other parts of the device.

It is an object of this invention to provide an improved float support arrangement of the above described character, having an economical construction, and facilitating assembly, and access to parts for adjustment or replacement.

It is a further object of this invention to provide a novel and improved, methdd of securely mounting a float lever pivot pin.

Other objects will appear from the following description and accompanying drawing, referring to which:

Figure l is a vertical sectional view of a carburetor embodying my invention.

Figure 2 is a plan view of the carburetor shown in Figure 1 with parts broken away for better disclosure.

Figure 3 is a sectional view taken on line 3-3 of Figure 1 in the direction of the arrows.

Figure 4 is a perspective view of the pivot retaining spring.

Figure 5 is a fragmentary view with parts re-. moved for clearer disclosure.

The reference numeral i indicates the main body member of the carburetor having a combination air horn and constant level chamber cover 2 attached thereto by any suitable means such as screws 3. A mixture conduit is formed by air inlet 4, venturi 5, mixing chamber 6 and mixture outlet 1. The air inlet is controlled by the choke valve 8 which is pivotally mounted on shaft 9 and may be operated manually by means of lever ill or by any suitable automatic or semiautomatic means. Throttle valve ll pivotally mounted on shaft l2 and operated by suitable means thru lever l3 controls the mixture outlet.

A constant level chamber I4 is formed in the main body member of the carburetor and a boss I5 having the horizontal threaded passage l6 therethru is provided for threaded engagement of inlet fitting II. -A threaded longitudinal passage i8 is provided at one end of the inlet fitting for conventional attachment of a fuel supply conduit and a concentric passage l9 at the opposite end of the fitting provides a guide for the flat sided body of the needle :valve 20, passages l8 and i9 being connected by a smaller passage 22 forming valve seat shoulder 2|.

Fuel is delivered to the constant level chamber from the main fuel supply tank by pump or gravity means and is admitted thereto thru the inlet fitting and a constantlevel of fuel, substantially as shown, is maintained within the constant level chamber by float 23 acting upon the needle valve 20 thru the float lever 24 which is rigidly attached to the float and pivotally mounted on float lever pin 25.

For the mounting ofthe float lever pin a pair of vertical grooves 26 are formed in opposite inner walls of the constant level chamber, and a float lever pin retainer 21 arranged for insertion in grooves 26 is provided for the purpose of confining the float lever pin to the lower end of the grooves, as indicated at 36, when the cover 2 is attached.

The construction and material of the float lever pin retainer 21 are preferably such as to permit at least some yieldability vertically and laterally, on account of the varying amount of compression of gasket 28 which may occur as the cover 2 is tightened down by screw 3 to effect a fuel tight seal, and also on account of the greater accuracy required and therefore more costly manufacture of a non-yieldable retainer. By using this yieldable construction, and by making the normal height of the member 21 slightly greater than the depth of the groove 26, I- insure a snug but free operating fit for the pin 25. The retainer is preferably, of such width that the ends must be distorted inwardly in assembly so as to frictionally grip the inner walls of the grooves. This facilitates assembly where the carburetors are progressively assembled in a production line, particularly where the same operator does not assemble the float support mechanism and the bowl cover.

I prefer to use a-low temper metal such as half hard brass or steel in the manufacture of the retainer, because of the lower cost and the ease with which it may be formed as compared with high temper metal. Suiflcient yieldability, both horizontally and vertically, is obtained by the general U-shape construction of the retainer, as indicated in the drawing. The thickness and width of the stock are of some importance, as the use of material too thick or too wide will interfere with the proper assembly and operation of the device. Without intending to limit myself to the use of these exact dimensions, I have found that stock twenty thousandths of an inch thick and one hundred and forty thousandths wide is admirably adapted for the purpose.

It will be understood that in the manufacture of the pivot pin and in the forming of the grooves 26 certain tolerances in dimensions are necessary; and within such dimensional limits a space between the end parts of the pivot pin and the bottoms of the grooves may occur as indicated at 31. To avoid any possibility of the ends of the retainer 21 slipping into this aforementioned space they are turned inward to form offset abutments or bearing portions as indicated at 38. This serves the double purpose of insuring correct location of the parts, and also presenting sufficient bearing area between the pin and the retainer to avoid excessive wear at that point.

Referring to Figure 5 of the drawing, it will be noted that grooves 26 are partially closed at their lower ends by projecting metal 39 which provides separating walls between the ends 38 of retainer 21 and bearings 40 of the float lever 24 and also provides guides for the more exact location of pin 25 which is considerably smaller in diameter than the width of grooves 26.

For normal and high speed engine operation,.

In operation air enters the mixing conduit thru inlet 4 and passes thru restriction 5 aspirating fuel from the jet 30 and low speed ports 32 according to the position of the throttle and the operating conditions of the engine in a manner well understood in the art.

The float, float lever 24, pin 25 and retainer may readily be removed or replaced upon removal of screws 3 and the combined air horn and float chamber cover 2. When the parts are in position as shown in Figure 1, the member 21 is slightly compressed between the cover 2 and the pin 25, so as to hold the pin firmly in position without interfering with its turning movement, so that the pin may be rotated with respect to either the float lever bearing 40 or the groove 26, or both.

The invention is not limited to the structure shown but may be modified in various respects Within the scope of the appended claims is contemplated.

I claim: p, 1

1. In a carburetor having a float chamber, float mechanism therein, and pivotal support means for said mechanism, said means comprising a pair of spaced grooves formed in the walls of said float chamber, pin parts on said float mechanism engaging and supported in said grooves, and a separate retaining structure in said grooves engaging said pin parts for retaining said parts in position in said grooves.

2. A constant level fuel chamber, having a pivoted float mechanism, a pivot pin for said float mechanism, a recess in one side of said constant level chamber, a threaded opening in the end wall of said recess for receiving a fuel inlet member, a pair of parallel vertical grooves in the side walls of said recess, the lower ends of said grooves forming bearings for said pivot pin, andsepto ports 32 thru low speed passages 33, 34,, and r arate means for retaining said lower ends of the said grooves.

3. In a carburetor, a float chamber having a cover member and parts with opposing vertical grooves and float support mechanism comprising a float pivot pin having an end supported in and engaging each of said grooves and a retainer for said pivot pin comprising a. substantially U- shape, flexible sheet metal member, said cover pivot pin at the member being constructed and arranged when applied to said chamber to contact the upper part of said retainer and thereby hold said float pivot nally within said groo'veand having an offset abutment at one end for engaging said pivot means and resisting movement thereof .longitudinally of said" groove.

6. Carburetor fuel chamber structure comprising parts having opposing grooves, float pivot means supported in said grooves, and a retainer for said pivot means comprising a U-shaped resilient strip with its ends friction-ally engaging the walls of said grooves and engaging said means.

7. Structure as specified in claim 6 in which said U-shaped retainer strip has bent elements at the ends of its leg portions for engaging said pivot means.

8. In a carburetor having a constant level fuel chamber, a recess in one side of said chamber forming a fuel inlet and having side structure, and grooves in said side structure for receiving float pivot means, said'structureincluding elements extending partly across the open sides of said grooves at the lower portions thereof and forming float pivot bearing structure.

9. Constant level chamber structure comprising a part having a groove, float pivot means in said groove, and. a pivot retainer also in said groove, said retainer being wider than said pivot means-and said part having an element extend-' ing partially across said groove and forming a restricted bearing portion therein for said pivot means.

10. Structure as specified in claim 9 in which said element extends across a portion of said retainer.

11. Constant level chamber structure comprising a part having a groove, a float pivot supported in said groove, and a retainer in said groove engaging said pivot, said groove being restricted adjacent said pivot to form a snug bearing portion therefor.

12. In a carburetor, a constant level fuel chamber, a cover for said fuel chamber, float mechanism in said chamber, and pivotal support means for said float mechanism comprising a pair of grooves in spaced portions of said fuelchamber, float pivot parts engaging said grooves, and separat retainer structure in said grooves and engaging said parts, said structure being frictionally maintained in position by its inherent resilience and said cover engaging said structure to additionally maintain said structure and said pivot parts in position.

FRED A. KOMMER. 

